1. Field of the Invention
The present invention relates to a screw press for extracting liquids from solid-liquid mixtures and, more particularly, addresses the issue of hydraulic capacity of a screw press inlet section.
2. Description of the Prior Art
It is widely known to use a screw press to extract liquids from a solid-liquid mixture, such as a pulp suspension.
Conventional screw presses typically include a perforated cylinder having axially spaced-apart inlet and outlet ends, and a screw rotatable within the perforated cylinder to compress and dewater a solid-liquid mixture as it is conveyed thereby from the inlet end to the outlet end of the perforated cylinder. The liquid is forced to drain across a perforated cylindrical screen surface extending axially between the inlet and outlet ends of the housing.
Although such conventional screw presses are effective, it has been found that it would be beneficial to improve the drainage capacities of the inlet end thereof and, thus, lift the restriction on the total admittable feed flow to the presses.
It is therefore an aim of the present invention to improve the dewatering performances in an inlet area of a screw press.
It is also an aim of the present invention to increase the surface available for drainage at an inlet end of a screw press.
Therefore, in accordance with the present invention, there is provided a screw press inlet section comprising a housing defining an axially extending chamber having a longitudinal axis and a radial inlet opening for receiving an incoming solid-liquid mixture. The chamber has an outboard end wall defining a plurality of liquid flow passages for allowing the same to act as a drainage surface.
In accordance with a further general aspect of the present invention, there is provided a screw press for extracting liquids from a solid-liquid mixture, comprising a housing having longitudinally spaced-apart inlet and outlet sections, and a pressing section between said inlet and outlet sections. A rotatable feed and compression screw is mounted within said housing for conveying the solid-liquid mixture from the inlet section to the outlet section while compressing and dewatering the liquid-solid mixture such that liquid is discharged from said housing. The inlet section has an outboard end wall defining a plurality of liquid flow passages for liquid to drain therethrough in a direction opposite to a general traveling direction of the solid-liquid mixture within the screw press.